Antimicrobial properties of Pediococcus acidilactici and Pediococcus pentosaceus isolated from silage

J Appl Microbiol. 2021 Jul 7. doi: 10.1111/jam.15205. Online ahead of print.

ABSTRACT

AIMS: The objective of this study was to isolate multifunctional bacteriocin-producing strains; to characterize the expressed bacteriocin for the control of Listeria monocytogenes and vancomycin-resistant Enterococcus; to evaluate safety of studied strains; and to explore their antifungal activity.

METHODS AND RESULTS: Two Pediococcus strains were isolated from silage samples obtained from an organic farm in Belogratchick, Bulgaria. The strains were identified by 16S rRNA sequencing analysis and characterized as bacteriocins producers. Strong antimicrobial activity was detected against more than 74 different strains of Listeria monocytogenes, 27 different vancomycin-resistant Enterococcus strains. In addition studied strains were able to inhibit the growth of strains of Alternaria alternate, Aspergillus flavus, Asp. niger, Cladosporium sphaerospermum, Penicillium chrysogenum and Pen. expansum. Some aspects of the antimicrobial mode of action were evaluated, including killing curves and aggregation properties. Both strains generated positive PCR results for the presence of pediocin PA-1, but not for other bacteriocins evaluated in this screening process. Metabolomic analysis of the cell-free supernatants from both strains was performed in order to explain the observed antifungal activity against different molds. According to PCA and PLS-DA score plot, P. acidilactici ST3522BG and P. pentosaceus ST3633BG were clearly clustered from control (MRS). Increases in the production of benzoic acid, 2-hydroxyisocaproic acid, β-phenyl-lactic acid, α-hydroxybutyric acid and 1,3-butanediol were recorded, these metabolites were previously described as antifungic.

CONCLUSIONS: P. acidilactici ST3522BG and P. pentosaceus ST3633BG were evaluated as producing bacteriocin strains with high specificity against Listeria and vancomycin-resistant Enterococcus species. In addition both investigated Pediococcus strains were evaluated as producer of effective antifungal metabolite with potential for inhibition of mycotoxin producing molds.

SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this report is a pioneer in evaluation of Pediococcus strains isolated from silage with highly specific bacteriocinogenic antimicrobial activity against Listeria spp. and vancomycin-resistant Enterococcus spp., and antifungal activity against mycotoxin producing molds.

PMID:34231288 | DOI:10.1111/jam.15205

Source: Industry